Process for preparing alkaline metals having high reactive power



PROCESS FOR PREPARING ALKALINE METALS HAVING HIGH REAQTIVE POWER NDrawing. Filed Mar 18, 1957, Ser. No. 646,553 Claims priority,application Italy Mar. 23, 1956 7 Claims- (Cl. 260-665) It is known thatsome hydrocarbons add finely distributed alkaline metals (Schlenk, Ben,47, 473 (1914) )1 These hydrocarbons possess conjugated double bondsactivated by aromatic groups which may be either simple or conjugated.it is also known that these hydrocarbons can add normally two metalatoms, by giving up one of those activated double bonds and inexceptional cases even only one single metal atom. In, most cases theseadditions of metals are efiected in ether or in a cyclic ether in theabsence of water and, of the oxygen of air.

It has now been found and this represents. the object of the presentinvention, that these hydrocarbons are able to add not only two atoms ofmetal, as is indicated in the literature, but, under suitable operatingconditions, a sensibly greater number of metal atoms per molecule ofnon-saturated hydrocarbon.

In many cases this alkali-metal linked inrexcess gives the samereactions that are caused by the free alkalimetal. I

It is not possible to define accurately the manner in which the quiteconsiderable quantities of alkaline metal are linked by thosehydrocarbons. It may be that the addition takes place by means of aprogressive dissolving of all the double links, that is, also of thoseof the aromatic series. However, it may also be that there is only asolid solution of the alkaline metal at the surface of the hydrocarbon.

If those hydrocarbons containing more than 'twomolecules of alkalinemetal per molecule of addition compound, are decomposed with alcohol orWater, a quantity of hydrogen is obtained which in most casescorresponds approximately to the quantity of x minus 2, Where xrepresents the quantity in molecules of alkaline metal that is absorbedby the hydrocarbon. It then for instance six molecules ofsodium-areabsorbed by one molecule of anthracene and the compound formedis decomposed with water, there is obtained a quantity of hydrogen thatcorresponds about to tour molecules of sodium.

What has been set forth hereinbefore is true with approximative accuracyonly in the case in which the first two molecules of sodium are absorbedwhile in mutual position 1,4, as happens with anthracene. If the firsttwo molecules of alkalinemetal have been added in position 1,2 duringthe decomposition there is obtained a quantity of hydrogen slightlygreater than would correspond to the formula x,-2.

The production of these addition compounds. of alkaline metals isextraordinarily simple. It is only necessary to treat with the alkalinemetal a suitable hydrocarbon in an inert solvent or in a suspendingmedium such as toluene, xylene, parafiin oil etc., preferably atelevated temperature and excluding water and the oxygen of air.

It is advantageous but not necessary to effect this treatment in such amanner that the hydrocarbon be treated with the alkaline metal at firstfor the duration of one or assignors, by mesne assign-.

tates Patent 2,948,762 Patented Aug. 9,

2 more hours in the cold and keeping then the temperature further forfrom one to three hours above the melting point of the alkaline metal.It may even be advantageous to add at the beginning a small quantity ofa metallorganic addition compound previously prepared.

The comparatively elevated temperature indicated above is notindispensable; however, with to reduce the duration of the reaction. Ifoperating at temperatures beyond the meltingpoint of the alkaline metal,it is not always necessary to employ the alkaline metal finelydistributed. It is possible to employ even pieces of any size. I iS'oitisnot always necessary toadd the wholequantity of alkaline metalthat one wants toadd tothe hydrocarbon, at once at the beginning,although this be the preferred method or production. Above all if itisdesired to carry out this reaction for the first time with a newhydrocarbon it may be advisable to use first only 2 molecules ofalkaline metalper molecule of desired addition compound and to addfurther alkaline metal after those molecules having been absorbedcompletely. These addition compounds appear as; heavy colored powders,mostly of black bluish color orblack towards brown color, which separatefrom the solvent or from the suspension medium in the shape ofafinesand.

Hydrocarbons suitable are for instance anthracene, phenanthrene,stilbene, diphenyl' butadiene, fulvene and others. V i I V Thealkaline-organic addition compounds containing more than two moleculesof metal per molecule of hydrocarbon, can be employedin lieu ofthealkaline metal, for instance-asreducing agents in organic 'dgemis'try orin the polymerization of butadiene catalyzed by means of alkali metal.These sodium compounds" and; processes of making them and uses asactuators ofj'catalysts are described but not claimed in; our copendingapplications Serial Nos. 646,552 and 646,554 filed March 18, 1957,

I Example-1 To 170 g. of anhydrous xylene in a nitrogen atmosphere thereare. added. 25.8 'g. of sodium finely comminuted, and: 20g; of'anth-racene. 'Fhe mixture is stirred at first for two hours at ordinarytemperaturefand then from 0.1 to 0.2 g. of e rsodiurn anthracene areadded. The mixture is slowly heated to C its color becomesintensive bluealready in thecold "on'as soonas the temperature begins 'to rise.{Thesodium 'whie at the beginning is perfectly "ble, slowlydisappears'coni pletelyand afiter three hours the reaction is terminatedand after stopping the stlrrerthe d'eca-sodiuni anthraceiie deposits asa sandy powder of bluish-black color under the. clear and colorlessl'i'qhi'd. For the analysis;- about 7 0.5 to 1 25' ml. are ut into asmall flask without exposin to contact 'with air. I Accurate weighing isuseless because the quantity of sodium obtained during the ex ert mentis determined afterwards'by tit-ration with 'nj/l tl H 804- The flaskisclosed with a dotible-borediruhber stopper. One of the bores serves toconnect the'small flask with a buret filled with water, "the otheronedor connecting with the upper part of ajBuntie bu-ret filled With waterthe lower part-of Whi'ch isconne'cted with a level vessel From-the buret"about 5 mllof waten are allowed to pass into the small flask, thelatter agitatedt the hydrogen. devlopedxis" brought into the Bunte buntby lowering the level vessel, this operation is repeated if needed untilno more hydrogen is found to develop and finally the flask is filledcompletely with water. Then the Bunte buret is closed and as usual thevolume of gas obtained is determined, from which the cubit centimetresof water are deducted which have been employed e for the decompositionof the sodium compound and for i filling the flask. Now the procedure ofusual titration] it is possible ther (b 49.65 cu. cm. of n/lO H SO=55.66 cu. cm. of

g. Hence the ratio b :a is equal to 1:0.78 or 10 mol:7.8 mol.

The ratio b ra is therefore equal to 1:0.77 or 10 mol:7.7 mol.

This corresponds for both analyses with good approximation to the valueof 10 moles to 8 moles.

Example 2 Into 150 g. of paraffin oil free from water and in a nitrogenatmosphere there are introduced 10.3 g. of comminuted sodium and 19.9 g.of anthracene. The mixture is stirred for four hours at normaltemperature, 0.1 g. of tetra-sodium anthracene is added and the mass isheated for three hours up to 110 C. In most cases already in the cold orat the beginning of heating, the suspension becomes dark-colored. Afterstopping the stirrer, the tetra-sodium anthracene formed separates fromthe clear and colorless liquid. The analysis (carried out as describedin Example 1) give the following data:

(I) Hydrogen developed by means of decomposition and collected abovewater, reduced to normal pressure and at C.;

(11 4.46 cu. cm.

(a 6.25 cu. cm.

(H) Titration with 12/10 sulfuric acid:

(b 9.15 cu. cm. of 12/10 H SO =10.25 cu. cm. of

(b 10.05 cu. cm. of n/ H SO =12.4 cu. cm. of

The ratio bza are equal to 1:0.44 and 1:05 respectively, whichcorresponds approximately to the ratio of 4 molecules to 2 molecules.

Example 3 To 200 g. of anhydrous xylene in nitrogen atmosphere there areadded 15.2 g. of finely comminuted sodium and 20 g. of stilbene. Themixture is stirred for 12 hours at normal temperature and in nitrogenatmosphere, 0.1 to 0.2 g. of di-sodium stilbene are added and understirring the mass is heated for 8 hours to 100 C. The suspension becomesdark-colored at once and after stopping the stirrer the hexa-sodiumstilbene separates in the shape of a brown-black colored powder. Theanalysis of two samples of the substance, carried out as described inExample 1, give the following values:

(I) Hydrogen developed by means of decomposition and collected abovewater, reduced to normal conditions:

(a 14.84 cu. cm.

(a,) 22.4 cu. cm.

(H) Titration with n/ 10 H 80 (b 17.55 cu. cm. of n/lO H SO 19.66 cu.cm. Of Hg.

(b;;) 25.9 cu. cm. of n/ 10 H;SO. ,=29.0 cu. of H The ratio b :a isequal to 1:0.77 and the ratio [1 x1 is equal to 1:075; this correspondsto a molecular ratio of 6245.

Example 4 To 150 g. of anhydrous xylene in nitrogen atmosphere there areadded 7 g. of comminuted sodium and 18.05 of anthracene. The mixture istreated as described in the preceding examples and a product is obtainedthe analytical values whereof, as indicated here below, correspond aboutto those of tri-sodium anthracene. During some experiments however it isfound that the anthracene added has not reacted completely. If allowingto rest, sometimes there deposits under the clear liquid also somenontransformed anthracene. It may be that a tri-sodium anthracene itselfdoes not exist and that a mixture is obtained of disodium anthracenewith other sodium anthracenes which contain more than two atoms ofsodium, such as for instance tetra-sodium or hexa-sodium anthracene. Itis also possible that during certain experiments made for the productionof di-sodium anthracene there are obtained compounds containing morethan two atoms of sodilnn, besides the anthracene not transformed. Theanalysis of the substance obtained during the experiment describedhereinbefore has given the following results:

(I) Hydrogen obtained by means of decomposition with water, reduced tonormal conditions:

(a 7.1 cu. cm.

(a 9.8 cu. cm.

(II) Titration with n/ 10 H ([2 22.63 cu. cm, of n/10 H SO =25.3 cu. cm.of H (12 29.47 cu. cm. of 12/10 H SO =33.0 cu. cm. of H The ratio of bzaare 3.56:1 and 3.33:1, which corresponds approximately to the ratio of 3molecules to 1 molecule.

We claim:

1. A process of forming an alkali-metal compound of a normally solidpolynuclear aromatic hydrocarbon containing 2-10 atoms alkali-metalcomprising stirring an alkali-metal with said aromatic hydrocarbon forat least about two hours in an inert anhydrous liquid hydrocarbon atatmospheric temperature under a non-oxidizing atmosphere and thenheating to about C. to about C. with stirring until a dark precipitateforms.

2. A process according to claim 1, wherein the aromatic compound isanthracene.

3. A process according to claim 1, wherein the aromatic compound isstilbene.

4. A process according to claim 1, wherein the aromatic compound isphenanthrene.

5. A process according to claim 1, wherein the aromatic compound isdiphenyl butadine.

6. A process according to claim 1, wherein the liquid hydrocarbon is abenzene homologue.

7. A process according to claim 1, wherein the liquid hydrocarbon isparaffin oil.

References Cited in the file of this patent UNITED STATES PATENTS2,183,847 Scott Dec. 19, 1939 2,194,450 Scott et al. Mar. 19, 19402,816,913 Frank et a1 Dec. 17, 1957 2,839,566 Lctsinger et a1 June 7,1958 OTHER REFERENCES Wooster et al.: Jour. Amer. Chem. Soc., vol. 53,June 1931, pages 179-187.

1. A PROCESS OF FORMING AND ALKALI-METAL COMPOUND OF A NORMALLY SOLIDPOLYNUCLEAR AROMATID HYDROCARBON CONTAINING 2-10 ATOMS ALKALI-METALCOMPRISING STIRRING AN ALKALI-METAL WITH SAID AROMATIC HYDROCARBON FORAT LEAST ABOUT TWO HOURS IN AN INERT ANHYDROUS LIQUID HYDROCARBON ATATMOSPHERIC TEMPERATURE UNDER A NON-OXIDIZING ATOMSPHERE AND THENHEATING TO ABOUT 100*C. TO ABOUT 110*C. WITH STIRRING UNTIL A DARKPRECIPITATE FORMS.